By car:
motorway A2, Exit "Seelisberg, Emmetten"
follow the signs to Seelisberg (approx. 12 kilometers)
By public transportation:
From Lucerne take the Lucerne-Stans-Engelberg railways (Zentralbahn) to Stans
In Stans, change to the post bus directly to Seelisberg

Other possibility:

Take the boat from Lucerne or Brunnen to Treib-Seelisberg and then change to the cablecar up to the village

Time table and more information: LINK TSB